AJs integrate global epithelial tension. (A) Myosin II in live wild-type or arm^M/Z embryos. Myosin II initially starts to form a meshwork in arm^M/Z (arrowheads), but the meshwork separates at discrete positions along the a-p axis. (B) Kymograph of actomyosin meshwork separation in an arm^M/Z embryo. (C) Tearing of the supracellular meshwork alters myosin II organization and dynamics. Myosin II fibers that normally extend between myosin II spots retract (blue arrows) in arm^M/Z embryos (i). Loss of cell adhesion in armRNAi embryos causes myosin II to form rings (red and blue arrows) that contract (ii). Contracted myosin II rings in armRNAi embryos exhibit continuous, unrestrained cortical flow of myosin II spots (colored arrows track myosin spots over time) into the ring (iii). Bars: (A) 10 µm; (B) 10 µm; (C) 5 µm.